There is no evidence yet that the Syrian military has actually begun the process of mixing precursor chemicals to produce deadly Sarin nerve gas, a senior defense official told NBC News on Tuesday.

According to the official, despite the increased activity around several chemical weapons sites, including truck movements in and out, it’s not even clear that the precursors have been moved from separate storage sites to one location.

On Monday, US officials said the Syrian regime has ordered its Chemical Weapons Corps to “be prepared” which was interpreted to mean get all the precursors and pieces together to at least begin preparations for weaponization.

The officials stressed the directive did not come directly from President Bashir Assad and did not order the use of chemical weapons. Those officials said yesterday, as the senior official repeated Tuesday that no evidence process has begun.